I take Howard's point and agree practicing 'mistakes' is counterproductive. However, if you're talking about full 5 & 6 string chords, you seldom really need to sound all the strings all the time. The first downbeat of a change is a good place to get the bass 2 or 3 strings, while the rest of your fingers scurry into place for the 1& or even the 2 beat. Even when you can make the full change quickly & seamlessly, partial chords are a good way to easily add a little sonic diversity.

Thanks for that reminder. I know that not all the strings need to be played with every stroke on open chords, but I'm always trying to get all the strings to sound on the barre chords. No doubt that's part of my frustration with them. I'll work on that.